June 2026
SUNSCREEN: A PRIMER
Summer often means long hours spent outdoors in the beautiful weather. This sacred time ushers in warmer weather and reminds us that we need to stock up on our SPF reserves ahead of the season to ensure that we can responsibly shield our skin. Now everyone can go outside, boost their mood and grab some much-needed Vitamin D.
Types of sunscreens
When choosing sun protection, it’s important to understand the different types of sunscreens and how each works to protect your skin. The active ingredients in sunscreens work by creating filters that keep harmful UV rays from penetrating the skin. There are two basic types of sunscreens: mineral and chemical. Each type uses different mechanisms for filtering UV rays and protecting the skin from damage.
Mineral sunscreens: Mineral sunscreens sit on top of the skin’s surface, acting as a physical block by deflecting and scattering UV rays away from the skin like tiny mirrors. Because they block UV rays at the surface level, mineral sunscreens protect against both UVA and UVB rays. Also, because mineral sunscreens create a physical barrier, they are effective as soon as they are applied, so there is no need to wait to go outside. While mineral sunscreens historically tended to have a whitish residue and were visible on the skin, this is no longer the case. The newer products cannot be seen on the skin and the mineral sunscreen ingredients are now in moisturizers, primers and foundation as well as actual sun protection products. Products are also now made to help the sunscreen stay applied, even with sweat and swimming. Mineral sunscreens contain the active ingredients zinc oxide and titanium oxide, or a combination of the two. These sunscreens are preferred by individuals with sensitive or acne-prone skin who want broad spectrum without irritation.
Chemical sunscreens: Chemical sunscreens are absorbed into the skin and sit in the deeper layers. They absorb UV rays and change them into heat, then release the heat from the skin. Since UV rays must penetrate the skin to reach these chemical, chemicals sunscreens may not protect against all UVA rays, which still cause damage to the deeper layers of the skin. Because chemical sunscreens take about 20 minutes to be effective, planning is required. Also, direct light causes the chemicals to be used up more quickly, so when you are in direct sunlight reapplication must be more frequent. The heat-releasing nature of chemical sunscreens can be problematic for sensitive and rosacea-prone skin, as well as for individuals with hyperpigmentation. The heated skin can cause an increase in existing brown spots. Chemical sunscreens can also clog pores and aggravate acne-prone skin. Chemical sunscreens contain oxybenzone, avobenzone, octinoxate, octocrylene, octisalate, homosalate or combinations thereof.
Concerns with chemical sunscreens: In 2021, the FDA reissued a proposed rule for over-the-counter sunscreen products that would require any active ingredient absorbed into the bloodstream at concentrations over 0.5 ng/mL to undergo toxicology testing, including carcinogenicity, and developmental and reproductive studies. Researchers have found that multiple ingredients found in chemical sunscreens find their way into the bloodstream, and the FDA recommended toxicology testing to investigate the clinical significance of these findings. Data from 2019 studies showed that 4 ingredients (avobenzone, oxybenzone, octocrylene, and ecamsule) exceeded the 0.5 ng/mL threshold after just one day of use. In some formulations, oxybenzone maximum plasma levels were recorded at concentrations in excess of 200 ng/mL There is particular concern about oxybenzone and its potential to affect hormone levels (potential endocrine-disrupting effects as well as affecting thyroid function) and cause allergic reactions. Oxybenzone was also found in urine, blood and breast milk and may be of particular risk to pregnant and nursing women. And in terms of the environment, oxybenzone is also harmful to the ocean’s coral reefs.
The mineral sunscreens zinc oxide and titanium oxide have enough safety data to be deemed safe and effective (GRASE), partly due to not being absorbed through the skin into the bloodstream.
Look at the ingredients in the product you use. Use a lotion-based sunscreen (not a spray) to reduce inhalation and lung exposure and to ensure thorough application. Don’t focus on SPF numbers, which can lead to misuse and an assumption of safety. Application quality matters more than SPF alone. Every sunscreen wears off, so reapply about every 2 hours while you’re out in the sun. And don’t skip it!